(a) Field of the Invention
The present invention relates to an apparatus for transmitting a packet within a delay time against a failure in transmitting the packet, which may occur due to an obstacle in a wireless sensor network installed on a road by using a wireless communication method in the wireless sensor network environment, and a method thereof.
(b) Description of the Related Art
Nodes constituting a sensor network installed on a road need to perform communication while adapting themselves to a rapidly changing channel environment in communication between the nodes. When an obstacle such as a vehicle, etc., is present between a transmission node and a reception node, a communication success ratio between the two nodes drops to a very low level. Therefore, it is impossible to predict the communication success ratio between the transmission and reception nodes at the time when the transmission node transmits a packet.
In the related art, proactive routing technologies such as a destination sequenced distance vector (DSDV), a wireless routing protocol (WRP), a clusterhead gateway switch routing (CGSR), etc., maintain the latest path information by periodically distributing a routing table to a terminal including path information to a destination. However, the proactive routing scheme has a large maintenance cost of a routing table and must periodically transmit the path information to the terminal regardless of the necessity of the path information.
Meanwhile, a reactive routing technology such an ad hoc on-demand distance vector routing (AODV), dynamic source routing (DSR), etc., finds a path by flooding a route request (RREQ) packet as necessary. This technology requires a long delay time for an initial path discovering time and has a problem in excessive flooding.
As such, the proactive routing and the reactive routing has a common point in previously determining a follow-up hop node on a path after previously determining a path to a destination before transmitting all packets. However, the proactive routing and the reactive routing are not suitable for a wireless sensor network system in a road environment in which it is actually impossible to predict the communication success ratio between the transmission and reception nodes at the time when the transmission node transmits the packet.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.